Added start of more conservative backlog markers
Switched to using past cycle time data, at a certain percentile, to power backlog markers.
Added true missing del
Tests pass
Added card data collection and display for TeamStats calls
Ensured histogram was sorted before pulling percentile data
Added histogram to team page
Put guarding around edge conditions, added average method to TeamStats
Provided recent metrics for team display, but log via comments the 12 week data used for backlog markers
Added conservative backlog markers based on team historical data. Fixes #139

Merge branch 't139'